Automatic bending machine



Jan. 26, 1954 A. FROEDGE AUTOMATIC SENDING MACHINE 2 Sheets-Sheet 1 Filed Sept. 12, 1952 IN V EN T 0R.' mggzaeqge,

BY X W ATTORNE Y5.

Jan. 26, 1954 A, L. FROEDGE AUTOMATIC BENDING MACHINE 2 Sheets-Sheet 2 Filed Sept. 12, 1952 M, zi iig BMQWW QQMM, I

ATTORNEYS.

Patented Jan. 26, 1954 UNITED STATES ATENT OFFICE Claims.

.Thisinvention relates to an automatic bending machine, and more especially to a head structure for :an automatic bending machine. The automatic bending machine and head structure of this invention can be advantageously employed for forming bends in various types of elongated metal stock such as rods, angles, channels, tubes, fiat stock, V-shaped stock, etc. However, the structures contemplated by this invention have particular utility for use in bending tubes or pipes of. generally circular cross-section.

.Itis a general object'ofthis invention to provide an'automatic bending machine of novel design which can be operated at the maximum speed at which .thepieces'of elongated metal stock can be fed. More'specifically in this connection, it is an 'object'of this invention to provide an automatic, pipe bending machine which is capable of making up to atleast i200 bends per hour ona .widevariety of difierent diameters of pipe. It is a further-object of this invention to provide an automatic bending machine, and more specifically a head structure therefor, which is particularly adapted to heavy duty work, for example, bending steel tubing of. up to at least 6 inches in diameter. It isa further specific object of this invention to provide a novel head structure for an automatic bending machine which substantially prevents. slippag between themain die wheeland thecl'amping die even though the faces of the die wheel and clamping die have become appreciably worn. Another specific object-is to provide adie wheel of novel configuration arranged .to coast with the clamping die to tightly clamp the work piece over'a substantial length thereof. It isalso an object of this invention to provide'meansfor applying increased clamping power between the die wheeland clamping die 'to firmly'hold the workpiece while the bend is being formed therein. Still anotherobiect of this invention is to provide a smoothly operating headstructure for an automatic bending machine, which operates without .jerkingor binding on both the bending and return movements, even though a large clamping pressure is applied. Another specific object of the inventionis to provide an automatic pipe bending machine which can be adjusted for the bending of various diameters of pipe. Further objects and advantages will appear as the specification proceeds.

-My invention is shownin an illustrative embodiment in the accompanying drawings, in which- -Figs. :l .to-.3 are fragmentaryoperational .plan views of a bending machinehead-structur embodying the principles of this invention, Fig. 1 showing the clamping die in retracted position with respect to the die Wheel, Fig. 2 showing the clamping die in advanced position at thebeginning of the bending operation, and Fig. 3 showing the position of the clamping die and die wheel at the completion of the bending operation; Fig. 4, an enlarged plan view of the bending machine structure illustrated in part in Figs. 1 to 3; Fig. 5, a cross-sectional view of the bending machine head structure taken on line 5-5 of Fig. 4; Fig. 6, an end elevational view of the head structure looking toward the right-hand end of the structure represented in Fig. 5; Fig. 7, a cross-sectional view looking in the same direction as the view of Fig. 6 taken on line 'l-l' of Fig. 5; and "Fig. 8, a fragmentary bottom cross-sectional view taken on line 8--8 of Fig. 5.

In one or its embodiments, this invention contemplates in an automatic'bending machine, the combination of a frame, a main shaft carried by the frame having a die wheel ailixed thereto, a hollow case pivotally mounted on the main shaft inwardly of the die wheel and projecting laterally from the shaft, a slideably mounted clamping die carried by the case and arranged for advancing and retracting movements with respect to the die wheel, and'means for actuating the clampingdie, including means for advancing and retracting the clamping die, and means for rotating the clamping die about the die wheel for a part of a revolution when the clamping die is in its advanced position. In this particular combination, the provision of a hollow case pivotallymounted on the main shaft is felt to be of particular importance for accomplishing the above objects. Further specific features and the advantages resulting therefrom will subsequently be discussed in detail.

Turning now to the drawings, and more particularly to'Figs.4-and 5 thereof, there is shown an automatic bending machine having a frame A providing spaced, horizontally-extending, upper and lower frame plates iii and H. The forward end portions of frame plates ill and H rotatably receive vertically-extending main shaft l2, as shown more clearly in Fig. 5. In the illustration given, cone bearings i3 and is are respectively provided in plates 1 l and id for rotatably receiving shaft i2.

The upper end of main shaft I2 is equipped with :an integral collar l5 spaced from the upper end of shaft .l 2 to provide a hub portion IE, which inturnis provided with a threaded bore as indicated at IT, and witha cross slot as indicatedat 18. The lower end of shaft 12 provides a reduced portion I9.

A hollow case, indicated generally at B, is pivotally mounted on main shaft l2. In the illustration given, case B, as shown more clearly in Figs. 6 and 7, is provided with a top wall 20, a bottom wall 2|, and side walls 22 and 23, which are rigidly locked together. Upper plate 2!! is rotatably received on hub portion it of shaft 12 and lower plate 2| is rotatably received on reduced portion ls'of shaft l2. It will be noted that case B extends laterally from shaft 12, and that top wall provides a bearing surface beneath die wheel 24. Die wheel 24 is rigidly affixed to the top of shaft l2 by means of a cross-tongue 25 interlocking with slot 18, and a headed stud 26 extending through an opening in die wheel 24 and threadedly seated within bore ll. It will be noted that die wheel 24 is coaxially aligned with shaft l2.

A double sprocket, consisting of an upper sprocket 21 integrally connected to a lower sprocket 28, is rotatably mounted on an intermediate portion of shaft l2. If desired, pin bearings 29 can be employed to provide the rotatable mounting. Means is provided for driving one of these sprockets. In the illustration given, this means consists of a chain 30 passing around upper sprocket 21 and extending rearwardly between frame plates It and H, as shown more clearly in Fig. 4. At a spaced distance from sprocket 21 and in alignment therewith, there is provided a guide sprocket 3! which is rotatably mounted on a shaft 32 supported by plates I9 and H. A hydraulic cylinder 33 is fixedly mounted intermediate sprocket 27 and sprocket 3 i. Cylinder 33 is provided with a double-acting piston 34 which has connecting rods 35 and 36 extending respectively from each side thereof through the adjacent ends of cylinder 33. The projecting end portions of connecting rods 35 and 36- are attached to the ends of driving chain 33, for example, as indicated at 31.

The bearing plate provided by upper wall 23 of case B is equipped with an elongated slot 38 which extends outwardly from die wheel 24, as indicated in Fig. 4. The sides of slot 38 preferably taper upwardly and inwardly, as indicated in Fig. and one side thereof can be provided with a gib or spacer 39. Slot 38 preferably receives the tapered head of a slide 43 in dovetail relation so that slide 40 moves back and forth within slot 38. In the illustration given, retaining plates 4| and 42 are provided for holding the head of slide 4!! within slot 38, as indicated more clearly in Figs.

6 and '7.

, to be shifted to various positions on slide 40, thus varying the outermost point of retraction of clamping die 43 with respect to die wheel 24.

Th laterally-extending portion of case B is provided with a rotatably mounted auxiliary shaft 4! in spaced parallel alignment with main shaft 12. In the illustration given, as illustrated more clearly in Figs. 5 and 7, case B is provided with an intermediate support plate 48 extending between the side walls 22 and 23 thereof, and with a hub support member 45 secured to lower 4 plate 2|. Shaft 41 is rotatably mounted within plate 48 and hub 49 by means of in bearings 50 and 5|,

Means are provided for driving shaft 41 consisting of a sprocket 52 rigidly mounted thereon between plate 43 and hub 49, and having an endless driving chain 53 extending there-around and around lower sprocket 28 on main shaft 12.

Crank means are preferably provided for advancing and retracting clamping die 43 relative to die wheel 24, said crank means being operated by the rotation of shaft 41 and, in turn, operating slide 40. In the illustration given, auxiliary shaft 41 is equipped at its top or upper end with an integral head 54 providing an upwardlyextending eccentric pin 55. Pin 55 pivotally carries one end of link 56, and the other end of link 56 is pivotally connected to slide 40 by means of pin 51. The lower end of pin 51, as seen more clearly in Fig. 5, projects below link 56 and is supported by L-shaped bracket 53. The outer end of bracket 58 is rigidly locked to the outer end of slide 49 by means of pin 59 and bolt 60. These members are arranged so that the revolution of auxiliary shaft 41 for part of a revolution in one direction advances clamping die 43, while upon shaft 41 reversing its direction of rotation, clamping die 43 is retracted and returned to its initial open position.

As seen more clearly in Fig. 4, die wheel 24 is preferably equipped with a tangential extension 6| providing a substantially straight clamping face 62 confronting the straight clamping face 63 of clamping die 43 and coacting therewith.

Main shaft [2 is preferably equipped with means for exerting a selectively predetermined frictional drag on the rotation of the shaft. This can be accomplished by providing an adjustable preloaded brake coacting with main shaft l2. Among the results accomplished by this are that shaft I2 and die 24 are prevented from rotating until the work piece has been firmly clamped between die faces 62 and 63. Another advantage is that smooth, non-jerky operation is obtained on both the bending and return movements of die wheel 24. In the illustration given, there is provided a brake drum 64, which is keyed to main shaft l2, as shown more clearly in Fig. 5. Brake drum 64 is positioned immediately below upper frame plate [0, which provides on each side of the brake drum downwardly-extending brake band supports 65 and 66. As shown more clearly in Fig. 8, pin 65 receives bracket 61 which is rigidly attached to a brake band loop 68 having its free ends provided with attachment eyes 69 and 10 Eyes 59 and 10 respectively receive the ends of J-bolts H and 12, which are spring-tensioned and extend through support projection 66. Between brake band 68 and the frictionally-engaged outer surface of brake drum 64 there is provided a brake lining 13.

Operation The operation of the automatic bending machine of this invention is illustrated in Figs. 1 to 3. Fig. 1 shows the members in their starting position with clamping die 43 fully retracted and with die faces 62 and 63 in facing relation. The work stock to be bent, inthis case a pipe P, has been fed into engagement with face 62 of diewheel 24. The rearward portion of pipe P rests against abutment or stop 14 to prevent the rearward portion of the pipe from rotating during the bending operation. Alternately, a feed tube of the conventional type can be provided for receiving the rearward portion of pipe P.

auntie" Pistdfr flwithin cylinder' fl is then frced' iary shaft 41 by means of endless chain 53., The. rotation' of shaft 47 operatedtlfe crank assembly" including head; IinR' S'BIiand slide 40,rso that clamping die 43' is advanceditowai'd die wh L 24. This movement contifiues until" the position is reached as indicated in Fig. 2, at which point pipe P is clamped between clamping die 43 and die wheel 24. From this point on, further rotation of shaft 41 produced in the manner described, causes case B to pivot on main shaft l2 until the position illustrated in Fig. 3 is reached. During this rotation, maximum clamping power continues to be applied between clamping die 43 and die wheel 24 so that pipe P is, in effect, wrapped around die wheel 24 to form the desired bend in pipe P.

On the return movement from the position indicated in Fig. 3, the piston 34 of cylinder 33 is driven in the reverse direction by fluid entering through pipe 16 which in turn rotates sprockets 21 and 28, sprocket 52, and shaft 41 in the opposite direction. This movement causes the crank assembly to retract clamping die 43 so that it disengages from pipe P and permits the members to return to the position illustrated in Fig. 1, after the manual removal of pipe P by the operator.

While in the foregoing specification a specific embodiment of this invention has been described in considerable detail for purpose of illustration, it will be readily apparent to those skilled in the art that many of the details set forth can be varied widely without departing from the spirit of the invention.

I claim:

1. In an automatic bending machine, the combination of a frame, a main shaft carried by said frame having a coaxially aligned die wheel affixed to a projecting end thereof, two rigidly connected sprockets rotatably mounted on said main shaft, means for driving one of said sprockets for a part of a revolution first in one direction and then in the other, a hollow case pivotally supported on said main shaft and projecting laterally therefrom, said case providing a bearing plate inwardly of said die wheel having a slot therein extending outwardly from said die wheel, an auxiliary shaft rotatably mounted in said case in spaced parallel alignment with said main shaft and having its upper end terminatingat a spaced distance from said slot, a sprocket wheel rigidly mounted on said auxiliary shaft, chain means drivably connecting said auxiliary shaft sprocket with the other sprocket on said main shaft, a clamping die slideably mounted on said bearing plate over said slot therein in alignment with a clamping face of said die wheel, and crank means connecting said upper end of said auxiliary shaft with said clamping die through said slot for advancing and retracting said clamping die.

2. In an automatic bending machine, the combination of a frame, a vertically-extending rotatably mounted main shaft carried by said frame, a coaxially aligned die wheel rigidly connected to the top of said main shaft for rotation in unison therewith, two rigidly connected sprockets rotatably mounted on said main shaft, means for driving one of said sprockets for a part of a revolution first in one directionand then in the other, a hollow case pivotally supported on said main shaft with said sprockets there-withill; said-case extending laterally from saidimain shaft 'andproviding norizontal bearing plate beneath said die wheel} said bearirig*platehav inga slottherei-n extending outwardly from said die wheel, an. auxiliary shaft rotatably mounted in said casein spaced "parallel "alignment with said main sfiaffi and liavingiits upper-end terminatingaat; a spaced distancebelow said bearing.- plate slot assprocket wheel rigidly mountedion said'auxiliary shaft, chain means drivably con; necting .said auxiliary shaft sprocket Withthe other sprocket on saidmain shaft, a clamping die slideably mounted on said bearing plate for advancing and retracting movements relative to said die wheel along the line of said bearing plate slot, said clamping die having a die face confronting said die wheel, and crank means connecting the upper end of said auxiliary shaft with said clamping die through said bearing plate slot, said crank means being arranged to direct the advancing and retracting movements of said clamping die.

3. The combination of claim 2 which is characterized by the further fact that said main shaft is equipped with means for exerting a selectively predetermined frictional drag on the rotation of said main shaft.

4. The combination of claim 2 in which said means for driving one of said sprockets for part of a revolution first in one direction and then in the other comprises a guide sprocket rotatably mounted at a spaced distance from said driven sprocket and in alignment therewith, a hydraulic cylinder positioned between said sprockets having a double-acting piston therein, connecting rods extending from each side of said piston through the adjacent end of said cylinder, and

a chain having its opposite ends attached to the projecting ends of said connecting rods and passing around both of said sprockets.

5. In an automatic bending machine, the combination of a frame providing vertically-spaced horizontally-extending plate members, a vertically-extending rotatably mounted main shaft carried by said plate members and projecting upwardly and downwardly there-beyond, a hollow case member having upper, lower, and side plates, the upper plate of said case member being pivoted on the upwardly-projecting portion of said main shaft and the lower plate of said case member being pivoted on the downwardly-projecting portion of said main shaft, the upper plate of said case member providing a bearing plate, a coaxially aligned die wheel rigidly connected to the top of said main, shaft above said bearing plate, a double sprocket rotatably mounted on said shaft, means for driving one of .said sprockets of said double sprocket for part of a revolution first in one direction and then in the other, said bearing plate having a slot therein extending outwardly from said die wheel, an auxiliary shaft rotatably mounted in said case in spaced parallel alignment with said main shaft and having its upper end terminating at a spaced distance below said bearing plate slot,.a sprocket wheel rigidly mounted on said auxiliary shaft, chain means drivably connecting said auxiliary shaft sprocket with the other sprocket of said double sprocket, a clamping die slideably mounted on said hear-'- ing plate for advancing and retracting movements relative to said die wheel along the line of said bearing plate slot, a slide member slideably mounted within said slot and carrying said clamping die, and crank means connecting the upper end of said auxiliary shaft with said slide 7 8 member, said crank means being arranged to di Number y i Name Date; rect the advancing and retracting movements of 2,403,323 .Adreon Ju1y 2, 1946 said slide member and clamping die. 2,411,801 ,Neilsen Nov. 26, 1946 ANDREW, L. FROEDGE. 2,469,405 Payne May 10, 1949- References Cited in the file of this patent ,7 S G E PATENTS D Num er oun ry a. e V UNITED STATES PATENTS 627,458 Germany Mar. 25, 1936' Number Name Date 471,658 Great Britain Sept. 8, 1937,

681,334 McKibben Aug. 27, 1901 7 50 3 2,312,122 Parker Feb. 23, 1943 2,357,873 Bower Sept. 12, 1944 GreatrB'ritain Feb. 28, 1951.v 

